1. Field of the Invention
The present invention relates to methods and systems of allocating data for subsequent retrieval.
2. Background Art
Peer-to-peer (P2P) file-sharing technologies may be grouped into categories based on the methods used for content identification, caching, and delivery. A first category of P2P technology may be characterized by a central index showing the locations (IP address) of content files shared on a segment of the network. When a data source is identified, a direct transfer of the entire file from one peer to another is facilitated by the network software.
A second category of P2P technology may be characterized by the content indices being distributed among a group of interconnected “super nodes” on the network. Often, an Internet subscriber hosting a super node on his/her computer would be unaware of it. Similar to the first generation P2P technology, when a data source is identified, a direct transfer of the entire file from one peer to another is facilitated by the network software. Many of the P2P applications currently in use (in particular those based on the so-called “FastTrack” protocol) are of this type.
Media on demand (MOD) systems may be characterized by centralized storage and one-to-one downstream transport. In a typical media distribution system, such as a video-on-demand system or music download service, the files may be distributed to individual subscribers from a centralized file-server (centralized storage). The file-server may be located on the cable operator's internal network (upstream from the video headend or CMTS) or network backbone. When a customer desires a media selection, the media may be routed from the file server to the subscriber via the CMTS or video headend. Thus the “last mile” transport burden is placed entirely on the downstream channel (one-to-one transport).
P2P systems may be characterized by media storage on subscriber devices connected to the access network. First and second generation technologies mimic the conventional MOD architecture on a small scale with files being served from a subscriber's home computer. In order to be transferred to another broadband user anywhere on the Internet, a file must be uploaded from the source subscriber's computer over the access network, transit the Internet, and be downloaded over the access network to the downloading subscriber. This may place a heavy burden on the upstream access network exacerbated by one-to-one content delivery. Connection times used by first and second generation P2P systems can be of long duration, sometimes persisting for days on an unmonitored computer running a P2P application. For example, if a high-speed data subscriber is provisioned with a 500 Kbps upstream data rate, it would take nearly 4.5 hours to transfer a 1 Gbyte media file to another subscriber.